Is this getting flagged? It's currently near the bottom of page 4, and should be in the top 10 of page 1. Are HN'ers just bitter / skeptical of these numbers?
I don't know why it's falling away from the front page, but as far as skepticism goes, numbers that surprising raise more questions than answers. Your anecdotes have been very informative by the way.
Controversial items can sometimes fall due to the anti-flamewar code. If it thinks the article is generating a flamewar in the comments it will get sunk.